It is necessary to protect a copyright in the case of dealing with data, for which copyright protection is necessary, such as a new movie, a TV program or music of a fee charging broadcast. As an effective method of protecting a copyright, there is the method of limiting the utilization of data by encrypting the data of which the copyright requires protection.
For example, at the time of the transmission of audio and visual data (hereinafter denoted as AV data), in the case that copyright protection is necessary for the AV data, the AV data is encrypted before being transmitted. As an example of the above, IEEE1394-DTCP (digital transmission protection) system has become a standard.
IEEE1394 allows data to be synchronously transmitted by means of a fast bus system that carries out a serial transmission and, therefore, it is possible to transmit AV data, or the like, in real time. This IEEE1394 system is being installed in a variety of digital audio and visual equipment, including household digital AV equipment as an external interface.
According to the IEEE1394-DTCP system, a certification function and the function of the nullification of a key are provided at the time of data transmission via an IEEE1394 bus so that the copyright protection can be-realized by encrypting data for which copyright protection is necessary, such as AV data before being transmitted.
Now, together with the spread and development of personal computers, a large number of recording apparatuses or reproduction apparatuses, such as a hard disk apparatus, have come into use, due to their large storage capacity and due to their high speed of access, as external memory apparatuses. Furthermore, hard disk apparatuses have recently come into use not only in computers but also in digital AV equipment, or the like, where video and sound are recorded and reproduced by applying digital technology so as to make use of their high speed of access and their large storage capacity.
Accordingly, there have been cases where a creator of a movie, and the like, consider that a third party should not be allowed to freely make copies of data prepared by themselves. Therefore, there exists data that is prohibited from being copied in another recording medium and there exists data that is allowed to be copied only one time in order to protect the copyright thereof.
In the case that such data is stored in, for example, an HDD by being copied, the data is reproduced by using only the HDD.
In addition, as one way of viewing a TV broadcast that has been conventionally widely used, a program (content) that has been broadcast is temporarily recorded in a recording apparatus, such as a VTR, so that the recorded data is reproduced at a later time and, thereby, the program is viewed at a time different from its original broadcast time.
In particular, in the case that a recording medium such as a hard disk where a random access is possible and where recording and reproduction are possible at the same time is used for a recording apparatus, a time shift reproduction, according to a narrow definition, can be implemented in a manner such that the content of a program can be viewed in sequence without any portion being missed even after being delayed for only a short period of time during the broadcasting time of the program in comparison with a VTR wherein a conventional tape medium is used.
FIG. 43 is a configuration diagram of a recording and reproduction apparatus for implementing a time shift reproduction according to the prior art. As shown in the figure, a recording and reproduction means 2120 is a means of recording and reproducing broadcasts inputted from the outside, a recording medium 2130 is a means of storing data of broadcasts that can be implemented by a hard disk, or the like, a switching means 2160 is a means of receiving inputs from the recording and reproduction means 2120 and inputs of broadcasts from the outside and for selecting any of them which is then outputted to an external monitor, or the like.
An example of the operation of a recording and reproduction apparatus according to the prior art that has such a configuration is described in the following.
First, in the case that a viewer is viewing a program in real time, the switching means 2160 carries out a setting such that the broadcast inputted from the outside is outputted to the monitor without change while the recording and reproduction means 2120 records the same program content in the recording medium 2130.
Next, in the case that the viewer returns again to a position in front of the monitor so as to restart viewing of the program after temporarily leaving the position in front of the monitor, the recording and reproduction means 2120 reproduces the recorded data from the point in time when the viewer left the position in front of the monitor while the switching means 2160 carries out the setting such that input from the recording and reproduction means 2120 is outputted to the monitor. After this, the viewer views the reproduction output from the recording and reproduction means 2120 as the program.
In the above described operation, the recording and reproduction means 2120 reproduces data while carrying out the recording of the broadcast inputted from the outside in a parallel manner. That is to say, the recording and reproduction means 2120 simultaneously carries out the reproduction and the recording of the data.
Thereby, even in the case that the viewer has to temporarily interrupt the viewing of a real time broadcast program, it becomes possible to view and to follow the content of the program without a gap, with a delay in accordance with the period of time, only, of interruption of viewing.
In the same manner as in the case of the transmission of AV data, however, a system for copyright protection is necessary in the case that AV data that requires copyright protection is recorded in and/or reproduced from a recording medium, such as a hard disk apparatus. How the copyright is protected, however, is not concretely determined in the case that AV data that requires copyright protection is recorded in and/or reproduced from a recording apparatus and/or reproduction apparatus.
In addition, in some cases copyright protection is required, in the same manner as for AV data, for document data sent via the Internet, or the like, and for computer programs, such as game software, in addition to AV data. How the copyright is protected, however, is not concretely determined in the case that the above described data that requires copyright protection is recorded in and/or reproduced from a recording apparatus and/or reproduction apparatus.
That is to say, there is a problem wherein there is no concrete system that protects the copyright in the case that AV data, document data or data such as computer programs are recorded in a recording apparatus and/or in the case that these types of data are reproduced in a reproduction apparatus.
In addition, when the remaining capacity for data recording in the above described HDD becomes small, it becomes necessary to overwrite new data on the data recorded in the HDD or to increase the remaining capacity by eliminating a portion of data that is recorded in the HDD. However, the user of the HDD considers that overwriting the data that is recorded in the HDD or the elimination of the data is not desirable and, in some cases, the user considers it desirable to copy the data recorded in the HDD in another recording medium.
On the other hand, as described above, the copyright holder is negatively affected when the data recorded in the HDD is copied by ignoring the copyright.
That is to say, in the case that data, for which copyright protection is necessary, is recorded in a recording apparatus such as an HDD, there is a problem that the user cannot copy the data to another recording medium.
In addition, the problem of copyright is taken into consideration with respect to broadcast programs together with the verification of broadcast type such as cable TV or a CS broadcast and digitalization of signals and broadcasts of programs are implemented, wherein recording for copying is set to be impossible in advance by including a copy guard in signals.
In a conventional recording and reproduction apparatus, however, a problem arises in that there is a risk that the recording of a program in the recording medium 2130 in order to implement a time shift reproduction causes an infringement of the copyright with respect to the program, when the copyright is taken into consideration as described above.
That is to say, a problem arises in that there is a risk that an infringement of the copyright with respect to a program, for which copyright protection is necessary, may be caused in the case that a time shift reproduction of the program is implemented.
As for measures for avoiding such a problem, methods of (1) limiting the times when time shifting is possible, (2) preventing the content that is broadcast from being stored in a complete form have been considered, and so on.